Recently, there has been used a method (e.g., a MOCVD (Metal-Organic Chemical Vapour Deposition) method) for forming a film on a target substrate by using, e.g., a metal-organic raw material gas. Many of the metal-organic raw material gases are in a solid state at normal temperature and pressure.
In order to use the solid raw material for the film formation, the solid raw material needs to be sublimated and supplied to a film formation system. The solid raw material is sublimated by, e.g., heating and then, the sublimed raw material is supplied to the film formation system together with a carrier gas.    Patent Document 1: Japanese Patent Laid-open Application No. 2004-140328
However, most of solid raw materials are of powder forms having particles of different diameters. Thus, when convection is caused by heating, or when a carrier gas is used, the solid raw materials in the form of powders, especially those having small particle diameters, may be blown away to be supplied to the film formation system.
If the particles are supplied to the film formation system, they may be incorporated into a film during film formation and also may deteriorate quality of the film formation, e.g., a production yield of semiconductor devices or the like.